1. Field of the Invention
The present invention relates to an oven in accordance with the introduction to the main claim.
2. Description of the Related Art
A usual oven provided with a browning or grilling member (known hereinafter simply as “grill”) comprises a box structure or housing comprising side walls, a rear wall, an upper wall and a lower wall, the walls bounding and defining an oven cavity presenting an opening at which a movable part is present.
In proximity to one of these walls, usually the upper wall, the grill is provided, having the form of an electrical resistance element, normally a tubular resistive element or a radiant electrical element; this grill presents a first side facing the top of the oven, and a second side (opposite the first), facing the interior of the oven cavity to hence irradiate a food item positioned therein (for example on a usual grid or support) and subject it grilling or surface browning.
Usually the cavity walls of a commercial oven are of metal covered with a layer of porcelain enamel having a certain emissivity level resulting in a compromise in the food cooking performance between oven cooking functions and grill cooking functions. This emissivity is typically within the range between 0.8 and 0.9. Moreover, these enamelling technologies are associated with complexity and production costs more compatible with mass production, and consequently widely used.
These oven wall characteristics, in particular of the upper wall, which is most influenced by the grill element, are therefore not optimal for each of the individual cooking modes in that, with regard to the grilling function, the energy radiated by the first side of the grill is absorbed in large percentage by the emissive material of the upper wall faced by that side. This reduces the oven radiation efficiency, whereas for “oven” cooking functions the emissivity of that oven wall in proximity to the heating element is not high enough to obtain optimal heating uniformity of the the oven wall, to which optimal cooking performance corresponds. In other words, a normally emissive wall enables only a minimal portion of the energy radiated by the first side of the grill irradiates the food item which, in contrast, receives virtually only the energy radiated by the second grill side, whereas the wall is not heated in an optimally uniform manner for the “oven” cooking functions.
All this limits the oven functionality, so prolonging the time required for cooking and for obtaining a browning or grilling effect on the food item.
Radiation reflector elements are also known as accessories to usual ovens provided with ceramic-covered walls, which improve only the grilling function, while leaving the oven cooking performance unvaried.